The invention discloses a stainless steel passivation process which is mainly technically characterized by taking citric acid and hydrogen peroxide as main compositions of a passivation solution and optimally selecting a volume fraction formula and a process of the stainless steel passivation fluid as follows:3 percent of the citric acid, 10 percent of the hydrogen peroxide, 5 percent of Citric Acid Passivation of Stainless Steel - Astro Pak
- Compromised Corrosion ResistanceChemical PassivationPutting The Solutions to The TestSignificant ResultsTechnological AdvancesCleaner, GreenerThe Other, Better StandardThe chemical treatment removing the free iron from the surface of stainless steel is called passivation. The chemical used is most commonly nitric acid (HNO3), a highly corrosive mineral acid. This acid was specifically called for in SAE AMS-QQ-P-35 which was the standard used throughout the aerospace industry into 2005. However, as early as the turn of this century, there was increased interest in a viable alternative using citric acid (C6H8O7), a weak organic acid that occurs naturally in citrus fruits. At the tiRAMCO Equipment Citric Acid Passivation - RAMCO Parts Nitric acid is by far the most accepted means by which passivation is performed. Recently, however, there has been an increase in the amount of industries that have successfully implemented citric acid into their passivation procedures. Citric acid is an organic acid unlike nitric which is a mineral acid.
The citric acid also works to enrich the chromium concentration at the surface of the metal. The citric acid passivation process is used very successfully in the pharmaceutical, medical and semiconductor industries, and produces superior results to the use of nitric acid alone, which has continued in use for historical reasons. PASSIVATION - H&W Global IndustriesH&W Global offers high quality, cost effective passivation of stainless steel parts or components. There are many options available in passivating metals. At H&W, we offer both nitric and citric acid passivation, with variations in process time, acid temperature and concentration to Passivation of Stainless Steel ASTM A967, QQ-P-35, AMS Oct 15, 2013 · Method 2- Passivation in Citric Acid (4-10w% Citric Acid, various temperature/time ratios are offered and additional wetting agents and inhibitors are acceptable) The following types may be specified for Method 1:Type 1 Low temperature nitric acid with sodium dichromate (20-25v% nitric, 2-3w% sodium dichromate, 70-90F, 30 mins min)
When formulated correctly, citric acid produces excellent results in passivation of almost any stainless steel product. It is used for cleaning, brightening and passivation of other metals as well. Some industries using citric acid include fasteners, medical devices, semi-conductors, automotive and aerospace.Nitric vs Citric Acid Passivation - Advanced Plating Jul 11, 2019 · Citric Acid passivation was developed by Adolf Coors brewing company for the passivation of the inside of beer kegs. It offers an effective alternative to nitric passivation with less handling concerns and is consider environmentally friendly being on the GRAS (Generally Recognized as Safe) list for the FDA making it ideal for food and beverage applications.